In a mobile communication system, supporting mobility of a user equipment is mandatory. To this end, the user equipment continuously measures a quality of a serving cell currently providing a service and a quality of a neighboring cell. The user equipment reports a measurement result to a network at a proper time and the network then provides optimal mobility to the user equipment via handover and the like.
In order to provide information for helping a service provider operate the network as well as the mobility support, the user equipment performs a measurement for the specific purpose set up by the network and may be then able to report the corresponding measurement result to the network. For instance, the user equipment may receive broadcast information of a specific cell determined by the network. Based on the received broadcast information, the user equipment is able to report a cell identity (called a global cell identity) of the specific cell, location identification information (e.g., tracking area code) on a location to which the specific cell belongs, and other cell information (e.g., a presence or non-presence of membership in CSG (closed subscriber group) cell) to a serving cell.
While a user equipment is moving, if the user equipment confirms that a quality of a specific area is very poor via measurement, it may able to report location information on cells having poor quality and a measurement result to a network. Based on the report on the measurement results of user equipments helping the operation of the network, optimization of the network can be enhanced.
In a mobile communication system having a frequency reuse factor set to 1. mobility is mostly performed between different cells on the same frequency band. Hence, in order to secure good mobility of a user equipment, the user equipment needs to measure quality of neighbor cells having center frequency equal to that of a serving cell and cell information well. Thus, the measurement of a cell having a center frequency equal to that of a serving cell is called intra-frequency measurement. A user equipment performs intra-frequency measurement and then reports a result of the measurement to a network at a proper time, whereby the object of the corresponding measurement result can be achieved.
A mobile communication service provider may operate a network using a plurality of frequency bands. In case that a service of a communication system is provided on a plurality of frequency bands, in order to secure optimal mobility of a user equipment, the user equipment should be able to well measure qualities of neighbor cells having center frequency different from that of a serving cell and cell information. Thus, the measurement of a cell having a center frequency different from that of a serving cell is called inter-frequency measurement. A user equipment performs inter-frequency measurement and then reports a result of the measurement to a network at a proper time.
When a user equipment supports measurement of a heterogeneous network, the user equipment may be able to perform measurement on the heterogeneous network in accordance with a base station configuration. This measurement of the heterogeneous network is called inter-RAT (inter-radio access technology) measurement. For instance, RAT may include UTRAN (UMTS terrestrial radio access network) and GERAN (GSM EDGE radio access network) according to 3GPP Standard Specifications or may include CDMA 2000 system according to 3GPP2 Standard Specifications.
However, if a user equipment performs all the intra-frequency measurement, the inter-frequency measurement and the inter-RAT measurement, as mentioned in the foregoing description, it may cause a problem of power consumption of the user equipment. In particular, in case that carrier aggregation introduced by 3GPP LTE-A Standard is applied, since the user equipment may be able to communicate with a plurality of serving cells at the same time, the demand for a power-efficient measurement performing method is rising.